It drives me nuts when people post HUGE pictures ... because my main interface with LJ is the Friends Feed, and one 3,000+ width picture showing up in a post there makes EVERYTHING on that page scroll off the side. I'm guessing that this is due to people posting from their phones and just including a full-size multi-megapixel image with the post, as I can't imagine that anybody posting from the web would intentionally put in a pic that big.
I wish there was a "mute image" or somesuch button for those cases because it means that I pretty much have to read everything else on the page in "comment" mode, which is a pain in the ass.
Of course, the Millennials and "Gen Z" folks often JUST have phones and no real PCs, so they don't even consider the non-mobile viewing (I don't have a clue what a 3000px wide image in LJ looks like on a phone) rendering of what they're posting ... so it's no doubt going to get worse.
Grrrr ... GET OFF MY LAWN!